(1) Field of the Invention
This invention relates generally to measuring devices for use in medical applications and is directed more particularly to a device and method for measuring the length of a human urethra.
(2) Description of the Prior Art
Urinary incontinence is a widespread medical affliction suffered by approximately 11 million adults in the United States. There are in existence a variety of urethral occlusion devices to aid in the control of urinary incontinence. However, in order for certain occlusion devices to be comfortable and effective in minimizing leakage around the device, they must be accurately sized according to the length of the intended patient's urethra.
Several sizing devices for measuring body cavities are known in the art. In U.S. Pat. No. 5,352,182, there is disclosed a void-through urethral catheter and an accompanying sizing device to determine the proper size for the disclosed catheter. In use, the sizing device is first reconfigured so that it is sufficiently narrow in diameter for insertion into the urethra. Accordingly, a rod must be inserted into a shaft of the device until the rod contacts the mushroom-shaped distal end of the shaft. The rod is then advanced further, longitudinally extending the end of the shaft to reduce the diameter thereof. Using the rod, the shaft is inserted into the urethra and advanced until the device reaches the bladder. The rod is then removed, allowing the mushroom-shaped end of the shaft to drop against the bladder neck. A removable disk on the shaft's opposite end is moved along the shaft until it contacts the urethral meatus. Markings on the shaft indicate a range of catheter sizes, and the marking on the shaft where the disk abuts the meatus represents the particular size needed for proper fit.
The above-described device is deficient in that it requires the operator to read the marking on the shaft immediately adjacent to the external urethral meatus. It is difficult to obtain an accurate reading at this location due to the marking being obscured by the labial tissues. Also, since the disk is a thin, cylindrical object, it is difficult to manipulate with the fingers and properly position the disk due to the spongy nature of the urethral tissues, and further due to the positioning of the disk between the labia and the meatus.
Moreover, this sizing device is disadvantageous in that it requires the preliminary step of reconfiguring the shape of the device prior to insertion into the urethra. Further, it would appear that the disk must be slid onto the shaft after the shaft has been inserted into the urethra and secured in the bladder neck. This increases the steps required to configure the device for measuring and further illustrates the cumbersome nature of the device.
U.S. Pat. No. 4,500,313 discloses a urethral catheter that determines the length from the meatus to the sphincter. This catheter has an inner member open at an end adapted to be inserted into the urethra, and an outer sleeve into which the inner member is received. The inner member includes calibrated markings that are spaced from the open end of the inner member by a distance equal to the length of the outer sleeve.
To determine the length, the operator holds a flared end of the outer sleeve in a fixed position against the external meatus while feeding the inner member therethrough into the urethra. The inner member is advanced until urine enters its open end and flows through the inner member, indicating that the catheter is past the sphincter. The inner member is then withdrawn until the flow of urine stops, indicating that the device is below the sphincter. The length from the meatus to the sphincter is then determined by reading the calibrated marking on the inner member at the location of the non-flared end of the outer sleeve.
While the above device may be beneficial in that it allows for measurements to be taken at a distance from the meatus, the length from the meatus to the sphincter is not always an accurate representation of the length of the urethra because the location of the sphincter muscle varies from individual to individual. Thus, the device is of questionable use in determining an appropriately sized urethral occlusion device. The device is also cumbersome to use as it requires manipulations of the inner member until the sphincter is located. Once located, there is no means for anchoring the inner member in the bladder neck to prevent slippage therefrom while a reading is taken. Additionally, since the flow of urine and its subsequent stoppage is the indicator that the device is properly located for measuring, the device requires that there be sufficient urine present in the bladder to perform the measurement. Further, since urine is flowing into and through the inner member, the connection of a bag to the inner member is required to collect the urine. This increases the possibility that the operator may soil his hands with urine from the patient, resulting in an unsanitary procedure as well as requiring disposal of the collected urine.
There is thus a need for a urethral measuring device that eliminates the deficiencies in the prior art. The device must be simple in construction and easy to use, and must be capable of providing measurements irrespective of the volume of urine in the patient's bladder. The device must also be capable of providing accurate measurements of the length of the urethra which are easily observable while the device is positioned within the urethra.